Apparatus for producing an aerosol



APPARATUS FOR PRODUCING AN AEROSOL Aug. 5, 1969 R R' CURT'S ET 3,458,948

Filed July 7, 1967 v L" l' O 1o w3 Hu /m 556 n 65 Fig. 3 C

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Fig. 6 |5 |09 ALBERT' L. SCHLEMSKER O Flg. 4km, JAMES E Jwva UnitedStates Patent O U.S. Cl. 43-129 7 `Claims ABSTRACT OF THE DISCLOSURE Afog producing apparatus of the portable type having a heat exchanger,having excellent thermal efficiency, which is readily disassembled forcleaning without dismantling the fog producing apparatus.

Portions of the apparatus herein disclosed are disclosed and claimed inour copending patent application Ser. No. 651,838, led July 7, 1967assigned to the as signee of the present application.

BACKGROUND OF THE INVENTION Field f the invention The apparatus of theinvention, commonly called a fogger, is ideally suited for dispensingminute droplets of insecticides onto plants, shrubbery and the like. Itis to be understood, however, that the apparatus may be used fordispensing liquids other than insecticides. The housing encloses a heatexchanger connected to a nozzle and also supports a motor driven pumpwhich receives liquid from the reservoir and produces a pressurized flowof liquid through the heat exchanger for discharge from the nozzle. Ithas been found that many liquid insecticides contain a heat sensitivesubstance or chemical which produces, when heated, a film-like coatingon the inner wall surface forming the passageway through the heatexchanger. After intermittent operation of the fogger over a period oftime, the coat will build up to form a hardened layer or deposit liningthe passageway. This coating not only results in reducing the heattransfer efficiency of the heat exchanger but occasionally will iiakeoff in the form of small particles which are of suliicient size to clogthe nozzle or orifice.

SUMMARY OF THE INVENTION The apparatus of the present invention has animproved heat exchanger including a body in which a core is removablymounted for conveniently cleaning the liquid passageway through the heatexchanger; the passageway for fluid is cooperatively dened by the bodyand the core in such a manner as to provide for efficient and uniformheat transfer to the liquid flowing through the passageway, the mountingfor the core serving as the puller for conveniently removing the corefrom the body of the heat exchanger when it is desired to clean thepassageway through the heat exchanger.

BRIEF DESCRIPTION OF THE DRAWING The full nature of the invention willbe understood from the accompanying drawings and the followingdescription and claims.

FIG. 1 is an elevational View of a fogger constructed in accordance withthe invention and with a portion shown in section to show generally theinternal arrangement of the major components;

FIG. 2 is an elevational view of the forward end portion of the foggeras generally taken along the line 2 2 of FIG. 1;

FIG. 3 is a view of the heat exchanger as taken along the line 3-3 ofFIG. 1;

3,458,948 Patented Aug. 5, 1969 ice DESCRIPTION OF THE PREFERREDEMBODIMENT Referring to the drawing which illustrates a preferredembodiment of the invention, FIG. 1 shows a fogging apparatusconstructed in accordance with the invention and including a housing 10adapted to be formed as a plastic molding in two half sections and witha generally uniform wall thickness. The housing 10 basically includes ahollow forward portion 11, a hollow handle portion 12 and a rear bottomportion 13. A perforated plate 15 having holes 14 formed therein formsthe forward end wall of the housing portion 11. Apertures 16 are formedwithin the bottom portion 13 of the housing adjacent a downwardlyprojecting cylindrical boss 17 formed with internal threads. Acylindrical container 20 defining a liquid reservoir 22, includes a neckportion 23 which is threadably received within the boss 17 forconvenient removal.

A pump 25 is mounted on the bottom portion 13 of the housing 10 by atubular support member 27 so that the pump is suspended within thereservoir 22. The specific construction of the pump 25, however, formsno part of the present invention, and it is to be understood that anypump system may be employed. In general, however, the pump 25 includes ascreened inlet member 29 which is positioned adjacent the bottom of thecontainer 20. Preferably the pump is of the positive displacement typeand includes a piston (not shown) which is reciprocated through aconnecting rod 32 eccentrically connected to the shaft of an electricmotor 34. An axial flow fan blade 35 is also mounted on the shaft of themotor 34 for pulling cooling air in through the holes 16 and dischangesthe air through the housing 10 and out of the holes 14.

The pump 25 has an outlet which opens to passageway within a conduit 37connected to the pump. 'I'he ow through the conduit 37 from the pump 25is controlled by an actuating rod 38 which extends upwardly from thepump through the housing 10 to receive a push button 40 retained withinthe handle portion 12 of the housing 10. The push button 40 andactuating rod 38 are normally baised upwardly by a compression spring 41retained within the handle 12. The maximum flow of liquid through theconduit 37 is determined by a stop member 43 surrounding the upperportion actuating rod 38. The stop member is adjustable by manuallyturning a flow control knob 44 threadably received within the handleportion 12 of the housing.

An elongated heat exchanger 45 including a body 46, is supported, at itsinner end within the housing 10 by a plate 47 which extends across thehousing and is retained by slotted sockets 48 on the housing sides. Thefront end of the housing is supported by plate 15 as will subsequentlybe described. Referring to FIG. 3, a pair of electrical heating elements50 are mounted within the body 46 of the heat exchanger 45, the heatingelements being electrically connected together at their outer or forwardends and form terminal lportions 54 which are suitably connected througha thermostat 56 (FIG. 1) to an electrical power supply. As shown in FIG.1, the thermostat 56 is mounted on a ilat upper surface formed on theheat exchanger 45 so that the' thermostat directly senses thetemperature of the body 46 adjacent the discharge end of the heatexchanger.

An elongated tapering opening of circular cross-section is definedwithin the body 46 by a smooth tapering surface 60 (FIG. 3). A smallerconcentric opening 62 is formed within the inner end portion of the body46 for receiving theI fitting 59 which communicates with con duit 37.

Referring to FIG. 4, the forward end portion of the body 46 is providedwith upper and lower extending flange portions 65 in which are formedcorresponding threaded holes 66. An oval-shaped boss 68 projects fromthe forward surface of the flange portions 65 and is received within acorresponding shaped opening 69 (FIG. 2) formed in the plate 15.

An elongated core 70 (FIG. 3) is mounted within the opening formedwithin the body 46 and includes an outer surface 72 having a taper whichmates with the taper of the internal surface 60 defining the centralopening in body 46. As shown in FIG. 3, a helical groove 75 is formedwithin the tapering surface 72 of the core 70 and cooperates with thesurface 60 to define a helical passageway 77 communicating, through anaxial groove in the end portion of the core and then through fitting 59,with conduit 37.

The forward end of the helical passageway 77 is connected, by passage83, to an axially extending passageway 80 (FIG. 4) formed within theforward end portion 82 of the core 70. A threaded boss 84 projects fromthe forward end portion 82 of the core 70 and a nozzle member 85 havingan orifice housing 88. A discharge opening 90 is formed within the-forward end portion of the nozzle housing 88 and in alignment with theorifice 86. Air receiving ports 92 are formed within the nozzle housing88 surrounding the nozzle orifice 86.

The forward end portion 82 of the core 70 is provided with a cylindricalexternal surface which is somewhat smaller than the diameter of theinternal surface 60 of the body 46 and thereby forms an annular shoulder97 (FIG. 4) which is spaced inwardly, within the bore or opening, fromthe forward end faceI of the heat exchanger body. A resilient seal orpacking member 98 surrounds the core and is positioned against theshoulder 97. A cylindrical sleeve 100 is mounted on the forward endportion 82 of the core 70 and is positioned in 4front of the packing 98so that the forward end surface of the sleeve projects slightly from theend surface of the boss 68.

The retaining plate 105 (FIG. 5) includes a central opening forreceiving the forward end portion 82 of the core 70 and is spacedbetween the sleeve 100 and the rear surface of the nozzle retaininghousing 88. The plate 105 is formed downwardly along opposite sides toform parallel flanges 107 (FIG. 5) which strengthen the plate 105 andare spaced adjacent the core end portion 82 to engage the forward endsurface of the sleeve 100.

Slots 109 (FIG. 5) are formed on opposite ends of the plate 105 and arealigned with the threaded holes 66 formed within the flanges 65 andcorresponding aligne-d holes formed within the forward end wall 15 ofthe housing portion 11 for knurl-headed screws 110. Annular flanges 112are formed on the screws 110 and the flanges are spaced from the head ofthe screws 110 for receiving the slotted end portions of the plate 105therebetween.

As shown in FIG. 3, the forward end portion 82 of the core 70 isprovided with opposing flat surfaces 115 and correspondingly interttingflat surfaces are formed on the plate 105 to assure that the core 70 ismaintained in proper alignment within the body opening 59.

In operation, when the electrical heating elements 50 are energized, theindicating light 116 (FIG. 1) is also energized. When the heat exchangerbody 46 reaches a predetermined temperature, the thermostat 56 opens theelectrical circuit to the heating elements and deene-rgizes theindicating light 116 to indicate that fogger is ready for use. In amanner described in the copending patent application mentioned supra,liquid from the reservoir 22 is supplied to the heat exchanger throughthe conduit 37 by depressing the push button 40. The liquid travelsthrough the heat exchanger 45 within the helical formed passageway 77 sothat when the heated, pressurized liquid is discharged through thenozzle orifice 86, the liquid immediately vaporizes and the vapor mixeswith the cooler atmospheric air flowing in through the ports 92 and thevapor condenses to produce a fog.

After the fogger has been used for an extended period of time and it isdesirable to clean the surfaces defining t-he helical passageway 77within the heat exchanger 45, the core 70 can be conveniently removedsimply 'by unthreading the screws 110. This causes the screw flange 112to engage the retaining plate 105 whi-ch, in turn, engages the nozzlehousing 88 so that the core 70 is extracted from the taper opening. Withthe core removed, the spiral groove 75 and the internal surface 60 canbe conveniently cleaned with, for example, suitable wire brushes.

After the scale or hardened deposit has been removed from the core 70and lbody surface 60, the core is reinserted within the opening 59 andthe screws 110 are rethreaded into the corresponding openings 66.Tightening of the screws causes the flanges 107 of the plate 105 toexert an axial force on the sleeve and thereby compress the packing andseal member 98 against the core shoulder 97 to form a tight seal betweenthe end portion 82 of the core 70 and the internal surface 60 of thebody 46. The axial force also provides a firm contact between the outersurface 72 of the core 70 and the internal tapered bore 60 of the body.

From the drawing and the above description, it can be seen that foggerconst-ructed in accordance with the invention provides several desirablefeatures and advantages. For example, by constructing the heat exchanger45 with a conveniently removable core 70, any deposit which forms orcarbonizes on the surfaces which define the passageway 77 can beconveniently and easily Iremoved when desired to assure that the foggeroperates at maximum efliciency. The mating tapering surfaces 60 and 72also provides for a tight contact between the core 70 and housing 46 toprovide for efficient heat transfer from the body to the core.Furthermore, the heating of the liquid within the helical passageway 77has been found to provide uniform heat transfer from the heat exchangerto the liquid and thereby assure that the liquid is discharged at asubstantially uniform temperature.

Another important feature is provided by the construction andarrangement of the forward end portion of the heat exchanger includingthe spacing and the positioning of the plate between the sleeve 100 andnozzle retaining housing 88. That is, the plate 105 in conjunction withthe screws not only provide means for clamping and sealing the Icore 70within the body 46, but also provides for convenient but forcefulremoval of the core 70 when it is desirable to clean the helical grooves75 and surface 60 defining the liquid flow passageway 77 through theheat exchanger.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention.

The invention claimed is:

1. In an apparatus for producing a fog, including a housing having areservoir for holding liquid to be dispensed as a fog, a dischargenozzle from which vaporized liquid is discharged, and means forwithdrawing liquid from the reservoir; the improvement comprising a heatexchanger connected to receive liquid from said supply means and havingan outlet connected to said nozzle, said heat exchanger including ahollow body defining an opening 'which is connected to receive theliquid from said supply means and providing one surface of a vaporizingpassageway in said heat exchanger, a core member mounted within saidopening and cooperating therewith providing the remaining surface ofsaid passageway, an electrical heating element mounted in heatingexchange relationship in said body, and means adjacent the nozzlereleasably securing and mounting said core in said opening providingmeans for removal of the core for cleaning of the surface forming saidpassageway.

2. Apparatus as defined in claim 1 wherein said body is mounted inspaced relation to the walls of said housing and is substantiallyelongated in the direction of said opening, and wherein said core islikewise elongated to fill said opening and the cooperating passagewaydefining surfaces of said body and said core are constructed andarranged to define a passageway through which liquid is directed over adistance substantially longer than the length of said body.

3. Apparatus as defined in claim 2 wherein said means forming the outersurface of said core includes means defining a helical groove formedtherein along the length of said core for providing uniform rapid heattransfer from said electrical heating element means and said body to theliquid flowing within said groove and for providing convenient cleaningof said groove when said core is removed.

4. Apparatus as defined in claim 3 wherein said opening and said coreare formed with mating tapers, and said securing means include means forclamping said core longitudinally within said opening to provide a tightcontact between the outer surface of said core and said surface meansdefining said opening within said body for providing efiicient heattransfer to said core and to conne the liquid within said groove.

5. Apparatus as defined in claim 4 wherein said clamping means for saidcore includes means for pulling the core from said tapered opening toprovide for convenient removal of said core from said heat exchanger.

6. Apparatus as defined in claim 3 wherein said core includes adischarge end portion extending from the end of said body, means formounting said nozzle on said end portion, means forming an annularexternal shoulder on said end portion and positioned within saidopening, a ring seal surrounding said end portion and engaging saidsurface means defining said opening, an annular sleeve surrounding saidend portion, and clamp means for applying an axial force against saidsleeve to deform said seal for preventing liquid from flowing betweensaid end portion of said core and said surface means defining saidopening within said body.

7. Apparatus as defined in claim 6 wherein said clamp means include aplate mounted on said end portion of said core and located between saidsleeve and said nozzle, screw means extending through said plate andthreadedly engaging said body for drawing said plate against said sleeveto compress said seal, and means on said screw means for engaging saidplate when said screw means are turned in the opposite direction forpulling said core from said opening.

References Cited UNITED STATES PATENTS 3,134,191 5/1964 Davis 43-1293,229,409 l/ 1966 Johnson 43--129 3,242,098 3/ 1966 Andrews 252-3593,255,967 6/1966 Kenney 239-133 3,392,479 7/ 1968 Simmons 43-129 ALDRICHF. MEDBERY, Primary Examiner

